The present invention relates to an improved source of metalic material for metalizing apparatus.
It has been conventional in metalizing apparatus to use a source of metal in the form of a wire spool. The spool is mounted within a vacuum chamber, and unreeled to deliver the wire to a heated boat, where the wire is first melted into its liquid state and then vaporized. The spool is mounted in a position spaced away from the heated boat, so that only the terminal end of the wire is melted, as it reaches the boat. The spool is unreeled at a speed dependent on the metal input requirement for the metalizing process.
In order to guide the wire from the spool to the boat, a guide is employed, typically in the form of a tube having an interior diameter slightly larger than the cross-sectional dimensions of the wire, so that wire can be fed through the guide to the boat, as the spool is unwound.
During normal operation of conventional apparatus, the guide becomes clogged with metal material, which tends to accumulate and clog the outlet of the guide after some period of operation. This impedes the feeding of the wire from the spool to the boat, and in extreme cases can halt the feeding completely. In addition, the wire fed from the spool toward the boat tends to twist and kink, and the appearance of a severe kink can also halt the feeding of the wire. When the wire feeding is halted, the metalizing operation must be terminated, and maintenance performed on the wire feed within the vacuum chamber. This necessitates releasing the vacuum inside the metalizing chamber, whereby the vacuum must be restored later for subsequent operations. Thus, halting operation due to a malfunction in the wire feed is a costly and disadvantageous feature of conventional apparatus.